:root {
  color-scheme: light dark;
  --ink: #10161f;
  --ink-dim: #55606f;
  --ground: #f6f7f9;
  --panel: #ffffff;
  --line: #d9dee5;
  --beacon: #1c5fd6;
  --alarm: #a3231f;
}
@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e8ecf2; --ink-dim: #96a0ae; --ground: #0d1117; --panel: #151b23;
    --line: #262e3a; --beacon: #6ea3ff; --alarm: #ff8983;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0; min-height: 100vh; display: grid; place-items: center;
  background: var(--ground); color: var(--ink);
  font: 15px/1.55 system-ui, -apple-system, "Segoe UI", sans-serif;
  padding: 24px;
}
main {
  width: 100%; max-width: 26rem; background: var(--panel);
  border: 1px solid var(--line); border-radius: 10px; padding: 28px 26px 24px;
}
h1 { margin: 0; font-size: 1.35rem; letter-spacing: -0.01em; }
h2 { margin: 22px 0 6px; font-size: 1rem; }
.lede { margin: 2px 0 22px; color: var(--ink-dim); }
.hint { margin: 6px 0 0; color: var(--ink-dim); font-size: 0.86rem; }
label { display: block; margin: 14px 0 4px; font-size: 0.86rem; color: var(--ink-dim); }
input {
  width: 100%; padding: 9px 11px; font: inherit; color: var(--ink);
  background: var(--ground); border: 1px solid var(--line); border-radius: 6px;
}
input:focus-visible { outline: 2px solid var(--beacon); outline-offset: 1px; }
button {
  margin-top: 20px; width: 100%; padding: 10px; font: inherit; font-weight: 600;
  color: #fff; background: var(--beacon); border: 0; border-radius: 6px; cursor: pointer;
}
button:disabled { opacity: 0.55; cursor: default; }
button:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }
.message { margin: 16px 0 0; min-height: 1.2em; color: var(--alarm); font-size: 0.9rem; }
.key {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 1.05rem;
  letter-spacing: 0.08em; word-break: break-all; background: var(--ground);
  border: 1px solid var(--line); border-radius: 6px; padding: 10px 12px; margin: 8px 0 0;
}
.codes {
  list-style: none; padding: 0; margin: 10px 0 0; display: grid;
  grid-template-columns: 1fr 1fr; gap: 6px 14px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}
.who { font-weight: 600; margin: 0 0 4px; }
a { color: var(--beacon); }
[hidden] { display: none !important; }